1. Field of the Invention
The present invention relates to a speech synthesis system, and more particularly, to an apparatus and method for generating various types of synthesized speech by adjusting the friendliness of the speech output from a speech synthesizer.
2. Discussion of Related Art
A speech synthesizer is a device that synthesizes and outputs previously stored speech data in response to input text. The speech synthesizer is only capable of outputting speech data to a user in a predefined speech style.
With recent developments in the field of speech synthesis systems, demand for relatively soft speech such as conversation with an agent for intelligent robot service, voice messaging through a personal communication medium, and so forth, has increased. In other words, even though the same message is delivered, the degree of friendliness to a listener differs with the conversation situation, attitude toward the conversing party, and the object of the conversation. Therefore, various speech styles are required for conversational speech.
However, a currently used speech synthesizer uses synthesized speech in only one speech style, and thus is not suitable for expressing diverse emotions.
In order to solve this problem, simply, speech information in which utterances in various speech styles are mixed can be stored in a database and used. However, when the stored speech information only is used without consideration of various speech styles, synthesized speech of different styles end up being randomly mixed in a speech synthesizing process.